This invention relates to means for visually displaying message characters or symbols which are derived from coded information in the form of "on/off" states of a plurality of primary light sources. More particularly, the invention relates to a device or apparatus which utilizes a plurality of groups of light guiding optic fibers whereby light from one or more of a plurality of individual corresponding primary light sources is converted into meaningful message character-shaped arrays.
The use of light guiding "pipes" or optic fibers for communicating or conveying information from one point to another is known in the art and is disclosed, for example, in U.S. Pat. Nos. 3,043,179 and 3,109,065. Procedures have also been developed for assembling optic fiber bundles for use in specific applications, such as gastroscopes, endoscopes and vacuum tube faceplates as described in U.S. Pat. No. 3,215,029 and illuminated numerical display devices as described in U.S. Pat. No. 3,379,890.
Present standard industry practice for forming illuminated letter and/or numerical message character displays utilizes seven ("numeric") or sixteen ("alpha-numeric") bar-shaped segments not visible in an "off" condition but which become visible in an "on" condition by emitting light. Each "bar" segment is energized and illuminated independently or in combination with other segments to form a meaningful symbolic display. Present techniques, involving the use of light guiding optic fibers, as exemplified by U.S. Pat. No. 3,420,949, are restrictive in the number of light-guides used per bar-segment. Usually, an array of three light guides displaying three individual dots forms a single bar-segment, that is, one bar-segment is visually displayed by a series of three dots equally spaced apart from one another.
However, the foregoing practice of using arrays of separate "dots" to construct message character bar segments in a symbolic display device has prevented such devices from achieving total acceptability in situations where the amount of ambient light is great enough to diminish resolution and the degree of contrast between the illuminated "dots" and the dark-field background surrounding them to the point where legibility is seriously impaired. A need has therefore existed, particularly in avionic and outdoor applications, for visual message character display devices having greatly enhanced resolution and luminous intensity as compared with devices heretofore available.
Accordingly, it is an object of the present invention to provide visual message character display devices which give effective read-outs in environments having high ambient light levels.
Another object is to provide visual message character display devices for use in applications requiring low maintenance and easy replacement of parts.
Another object is to provide visible message character display devices of a design which facilitates low cost, rapid mass production thereof.
Yet another object is to provide a method for producing rapidly and at low cost visual message character display devices which give effective read-outs in environments having high ambient light levels and which require low maintenance and easy replacement of parts.
These and other objects of the present invention as well as a fuller understanding of the advantages thereof can be had by reference to the following detailed description, drawings and claims.